Hydrogen & s-Block · JEE Main previous year questions

2024 8 questions

1. Q652024 · 9 Apr 2024 · Shift 2
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: C

2. Q632024 · 6 Apr 2024 · Shift 2

   During the detection of acidic radical present in a salt, a student gets a pale yellow precipitate soluble with difficulty in ${\text{NH}}_4\text{OH}$ solution when sodium carbonate extract was first acidified with dil. ${\text{HNO}}_3$ and then ${\text{AgNO}}_3$ solution was added. This indicates presence of :

   1. A.${\text{I}}^{-}$
   2. B.${\text{CO}}_3^{2-}$
   3. C.${\text{Cl}}^{-}$
   4. D.${\text{Br}}^{-}$
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   Answer: D

3. Q802024 · 6 Apr 2024 · Shift 2

   Match List I with List II. | LIST I (Alkali Metal) | LIST II (Emission Wavelength in nm) | | :--- | :--- | | A. Li | I. 589.2 | | B. Na | II. 455.5 | | C. Rb | III. 670.8 | | D. Cs | IV. 780.0 | Choose the correct answer from the options given below :

   1. A.(A)-(II), (B)-(IV), (C)-(III), (D)-(I)
   2. B.(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
   3. C.(A)-(I), (B)-(IV), (C)-(III), (D)-(II)
   4. D.(A)-(IV), (B)-(II), (C)-(I), (D)-(III)
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   Answer: B

4. Q682024 · 31 Jan 2024 · Shift 1

   Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A: Alcohols react both as nucleophiles and electrophiles. Reason R: Alcohols react with active metals such as sodium, potassium and aluminum to yield corresponding alkoxides and liberate hydrogen. In the light of the above statements, choose the correct answer from the options given below:

   1. A.$A$ is false but $R$ is true.
   2. B.Both $A$ and $R$ are true but $R$ is NOT the correct explanation of $A$.
   3. C.Both $A$ and $R$ are true and $R$ is the correct explanation of $A$.
   4. D.$A$ is true but $R$ is false.
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   Answer: B

5. Q822024 · 30 Jan 2024 · Shift 1· Numerical answer

   The mass of sodium acetate ($\mathrm{C}{\mathrm{H}}_3\mathrm{COONa}$) required to prepare $250\text{ mL}$ of $0.35\text{ M}$ aqueous solution is _________ g. (Molar mass of $\mathrm{C}{\mathrm{H}}_3\mathrm{COONa}$ is $82.02{\text{ g mol}}^{-1}$)

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   Answer: 7

6. Q782024 · 29 Jan 2024 · Shift 1

   Appearance of blood red colour, on treatment of the sodium fusion extract of an organic compound with $\mathrm{FeS}{\mathrm{O}}_4$ in presence of concentrated ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ indicates the presence of element/s

   1. A.$\mathrm{Br}$
   2. B.$\mathrm{S}$
   3. C.$\mathrm{N}\mathrm{and}\mathrm{S}$
   4. D.$\mathrm{N}$
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   Answer: C

7. Q792024 · 29 Jan 2024 · Shift 1

   Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : Aryl halides cannot be prepared by replacement of hydroxyl group of phenol by halogen atom. Reason R : Phenols react with halogen acids violently. In the light of the above statements, choose the most appropriate from the options given below :

   1. A.A is true but R is false
   2. B.Both A and R are true but R is NOT the correct explanation of A
   3. C.A is false but R is true
   4. D.Both A and R are true and R is the correct explanation of A
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   Answer: A

8. Q772024 · 29 Jan 2024 · Shift 2

   Phenol treated with chloroform in presence of sodium hydroxide, which further hydrolyzed in presence of an acid results

   1. A.Salicylic acid
   2. B.Benzene-1,2-diol
   3. C.2-Hydroxybenzaldehyde
   4. D.Benzene-1,3-diol
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   Answer: C